add basic virtualization module

modules/virtualization/default.nix

@@ -0,0 +1,5 @@
+{
+  imports = [
+    ./virt-manager.nix
+  ];
+}

modules/virtualization/virt-manager.nix

@@ -0,0 +1,20 @@
+{ outputs, options, config, lib, pkgs, ...}:
+with lib;
+let
+  cfg = config.modules.virtualization.libvirtd;
+in
+{
+  options.modules.virtualization.libvirtd = {
+    enable = mkEnableOption false;
+  };
+
+  config = mkIf cfg.enable {
+    virtualization.libvirtd.enable = true;
+    programs.dconf.enable = true;
+    environtment.systemPackages = with pkgs; [
+      virt-manager
+    ];
+
+    users.users.sako.extraGroups = [ "libvirtd" ];
+  };
+}